8073519: schemagen does not report errors while generating xsd files

Reviewed-by: dfuchs

jaxws/src/jdk.xml.bind/share/classes/com/sun/tools/internal/jxc/SchemaGenerator.java

@@ -30,6 +30,7 @@ import com.sun.tools.internal.xjc.BadCommandLineException;
 import com.sun.xml.internal.bind.util.Which;
 
 import javax.lang.model.SourceVersion;
+import javax.tools.Diagnostic;
 import javax.tools.DiagnosticCollector;
 import javax.tools.JavaCompiler;
 import javax.tools.JavaFileObject;
@@ -248,7 +249,12 @@ public class SchemaGenerator {
             if (episode != null)
                 r.setEpisodeFile(episode);
             task.setProcessors(Collections.singleton(r));
-            return task.call();
+            boolean res = task.call();
+            //Print messages generated by compiler
+            for (Diagnostic<? extends JavaFileObject> d : diagnostics.getDiagnostics()) {
+                 System.err.println(d.toString());
+            }
+            return res;
         }
     }